HalavenThe US Food and Drug Administration has given green light to okyo-based Eisai’s eribulin mesylate (Halaven) as a treatment for women with advanced breast cancer after at least two prior chemotherapy regimens. The decision from FDA is more than six weeks earlier than the expected deadline for the review.

“The approval came earlier than I thought it would,” said Yasuhiro Nakazawa, an equities analyst at Mitsubishi UFJ Morgan Stanley Securities Co. in Tokyo, “The potential of the drug depends on whether it gets approvals to be used as the first and second line of treatments.”

The approval of Halaven, which is the company’s first original drug in the country in more than a decade, will help the Japanese company counter an expected loss of revenue to generic competition when the patent on its top-selling Aricept Alzheimer’s disease treatment expires Nov. 25.

Breast cancer is the second-leading cancer cause of death of among women, citing statistics from the National Cancer Institute. Some 207,090 women are expected to be diagnosed with breast cancer this year, resulting in 39,840 deaths.

Halaven, derived from a sea sponge, is believed to work by inhibiting cancer cell growth. Its safety and effectiveness were evaluated in clinical studies involving 762 women with metastatic breast cancer who had at least two prior chemotherapies for late-stage disease. Median survival was 13.1 months among those who took Halaven, compared to 10.6 months among those who didn’t get the drug, according to the US FDA. The most common adverse reactions were a decrease in white blood cells, anemia, hair loss, fatigue, nausea, nerve damage and constipation.

Other cancer drugs Xeloda from Roche and Ixempra from Bristol-Myers Squibb will be in competition on the market with the newly approved Halaven.